van Basshuysen, R. and Wilmers, G., "An Update of the Development on the New Audi NSU Rotary Engine Generation," SAE Technical Paper 780418, 1978, doi:10.4271/780418.
At AUDI NSU a new generation of rotary engines has been developed of which the significant layout parameters are outlined. The present status of development is characterized by a lean burn concept with fuel injection and an exhaust emission control system with catalytic converter. Test results indicate that the fuel economy ranges at the same level as comparable reciprocating engines. The future US-exhaust emission standards are kept below but in respect to the Japanese standards further reduction of NOx is necessary. Endurance tests proving the durability of the exhaust emission control system have still to be performed.